PowerPC AltiVec Built-in Functions

These built-in functions are available for the PowerPC family
of computers, depending on the command-line switches used.

The following machine modes are available for use with AltiVec built-in
functions (see Vector Extensions): V4SI for a vector of four
32-bit integers, V4SF for a vector of four 32-bit floating point
numbers, V8HI for a vector of eight 16-bit integers, and
V16QI for a vector of sixteen 8-bit integers.

The following functions are made available by including
<altivec.h> and using -maltivec and
-mabi=altivec. The functions implement the functionality
described in Motorola's AltiVec Programming Interface Manual.

Note: Only the <altivec.h> interface is supported.
Internally, GCC uses built-in functions to achieve the functionality in
the aforementioned header file, but they are not supported and are
subject to change without notice.